Make sure you have the latest version of simcraft, I just picked up LFR lei shen (switching from normal cha-yes) and gained 8k dps going from affliction to demonology. The past few releases have a clause that covers the trinket proccing.

If you're struggling to understand what Teye is asking, when you click on the 'Simulate' tab in simcraft after having imported your character, there should be a list of actions in descending order, which is known as the action priority list (APL). In there it should have the following lines, which cause the simulation to react to Perfect Aim procs.